Heavy-duty liquid detergent composition



* Jan. 28, 1969 SADAQ KAKEGAWA ET Al. 3,424,689

l HEAVY DUTYLIQUID DETERGENT COMPOSTION Filed Aug, 27, 1965 sheet of 2 new Jan. 2,8, 1969 sADAo KAKEGAWA ET AL 3,424,689

HEAVY DUTY-I JIQUID DETERGENT COMPOSITION Filed Aug. 27, 1965 sheet 2 of 2 United States Patent O 39/ 48,858 U.S. Cl. 252-137 2 Claims Int. Cl. Clld 3/066 The present invention relates to a detergent composition and more particularly to a transparent and homogeneous heavy-duty liquid detergent composition. Still more particularly it relates to a transparent and homo geneous heavy duty liquid detergent composition containing an aromatic monocarboxylate as a solubilizing agent in a mixture of a large proportion of polyphosphates and one or more noncationic surface active agents.

A light-duty liquid detergent composition has already been produced and has been used only for dishwashing and cleaning of ne fabrics. Since such a light-duty liquid detergent composition has, because of its composition, a relatively low soil-removing power, it is unsuitable for Washing heavily soiled cotton fabrics. On the other hand, a heavy-duty liquid detergent composition has an excellent soil-removing power an-d hence is most suitable for washing heavily soiled cotton fabrics and other textile goods. However, it is not always easy to provide such a high soil-removing power in a liquid detergent because a surface active agent, a main component of the heavyduty liquid detergent, is not compatible with polyphosphates or other inorganic builders, another main component of the heavy-duty liquid detergent, in an aqueous solution.

In order to improve the compatibility, two processes have been provided to date. In one of them, a nonionic surface active agent precipitated in an aqueous concentrated solution of polyphosphates is emulsied by using a high molecular weight compound as the emulsfying stabilizer. But the emulsion obtained by this process has faults such as, since the emulsion is opaque and has a high viscosity, it is inconvenient to use and further a strong agitation and a long period of time are required when the emulsion is dissolved or dispersed in water. Another process is one wherein the reduced solubility of a surface active agent in an aqueous concentrated solution of polyphosphates is improved by a solubilizing aid or a hydrotropic agent. The transparent and homogeneous liquid detergent obtained by the latter process is very convenient to use and is very similar in appearance to a lightduty liquid detergent composition. However, such a type of liquid detergent has the fault that, because known hydrotropic agents have a low limit in their solubilizing ability, it is impossible to maintain a mixture of a large -amount of surface active agents and polyphosphates in a transparent and homogeneous liquid and therefore there is a limit to the detergent power.

Therefore, an object of this invention is to provide an excellent heavy-duty liquid detergent composition based on the discovery of an excellent hydrotropic agent.

The heavy-duty liquid detergent composition according to this invention consists essentially of 5 to 30% by weight of one or more noncationic surface active agents, to 45% by weight of polyphosphates, l to 25% by weight of an aromatic monocarboxylate, and the balance water, which detergent composition is a transparent and homogeneous liquid in which the solid components are less than 75% by weight of the entire composition.

As the surface active agent to be used in this inven- ICC tion, there can be used an anionic surface active agent, namely, an alkylbenzene sulfonate having an alkyl group containing 8 to 15 carbon atoms, or a nonionic surface active agent polyoxyethylenenonylphenylether. These surface active agents may be used alone or as a mixture thereof. From the View points of detergent power and economy, it is preferable to use as the surface active agent a dodecylbenzene sulfonate.

As the salt of the anionic surface active agent used in this invention, an alkali metal salt or a lower alkanolamine salt thereof may be used. For example, a sodium salt, a potassium salt, an am-monium salt, an isopropanola-mine salt, and monoand tri-ethanolamine salts can be used, but considering the properties of other components in the detergent composition and the economic situation, an alkali metal salt, in particular, a potassium salt, of the surface active agent is most preferable.

A polyphosphate is a very important component in the heavy-duty detergent composition because it contributes to the prevention of precipitation of calcium compounds and lmagnesium compounds in an aqueous solution and gives an excellent soil-removing power to the detergent. As the polyphosphate there may be used potassium pyrophosphate and potassium tri-polyphosphate alone or as a mixt-ure thereof as the case may be.

A surface active agent and a polyphosphate are the main components of a heavy-duty detergent and it is no exaggeration to say that the detergent power of the detergent is predominantly influenced by the mixing ratio and the total amount of both components. However, in order to increase the content of the surface active agent and the polyphosphate in the detergent composition, an excellent hydrotropic agent is required. As a solubilizing agent conventionally used in liquid detergents, there are lower alcohols, such as, ethanol and isopropanol; polyols, such as, glycerol and propylene glycol; and so-called hydrotropic agents, such as, urea and p-toluene sulfonate. However, in the case where an alkaline inorganic builder such as a polyphosphate is present, the use of such alcohols and urea is unsuitable. Further, in the case of using a polyol or a lower alkylbenzene sulfonate, such as ptoluene sulfonate, there is a low limit in the amount of the surface active agent and a polyphosphate in the detergent composition, which makes difficult the production of a liquid detergent having an excellent Adetergent power.

These faults are overcome by the present invention. That is, the inventors have found that an aromatic monocarboxylate is an excellent solubilizing agent for obtaining a transparent aqueous solution of a noncationic surface active agent and one or more polyphosphates.

The aromatic monocarboxylate to be used in this invention is an alkali metal salt of acids having the following structure wherein R represents a hydrogen atom, a hydroxyl group, or an alkyl group having 1 to 3 carbon atoms. As typical examples of the aromatic monocarboxylates of this invention, there can be used the alkali metal salts of =benzoic acid, ethylbenzoic acid, p-toluic acid, p-cumic acid, salicylic acid and the like.

Hitherto, such aromatic monocarboxylates have been used as a solubilizing agent in the medical eld. For example, the use of sodium benzoate for dissolving caffeine in water is known. According to the reports by G. Noisillier et al. (Chemie et Industrie; vol. 90, No. 5, page 505 (1963) and ibid.; vol. 91, No. 3, page 263 (1964)), an aqueous sodium benzoate solution makes water-soluble a water-insoluble substance, such as phenol, and the mechanism resembles the solubilizing phenomenon by a surface 3 active agent. Also, it is reported by E. A. Vitalis et al. (U.S. Patent 2,441,341 (1948)) in the field of detergents that by mixing sodium benzoate in dioctyl sulfosuccinate, a water-soluble -powder causing no caking can be produced.

However, it has never been reported or attempted to use an aromatic monocarboxylate, such as sodium benzoate, in an aqueous polyphosphate solution as a solubilizing agent in the eld of detergents.

In order to dissolve transparently in an aqueous polyphosphate solution an anionic surface active agent, such as an alkylbenzene sulfonate, a lower alkylbenzene sulfonate, such as sodium p-toluene sulfonate and sodium mxylene sulfonate has hitherto been mainly used.

Also, hydrotropic agents are generally considered to be ineffective in the case of using as the main component a nonionic surface active agent, such as polyoxyethylene nonlyphenyl ether, and such agents have rarely been used. Therefore, in order to add transparently a nonionic surface active agent in an aqueous -polyphosphate solution, a process has been adopted wherein 20 to 30% by weight of a solvent, such as, propylene glycol or ethylene glycol, is used or the system is emulsied.

When the aromatic monocarboxylate of this invention is used as a solubilizing agent in such cases, the surface active agent and the polyphosphate are used in the detergent composition in a larger proportion than has been the case when conventional solubilizing agents or solvents are used, and this increases remarkably the value of the detergent in cleaning ability as well as in economy. Moreover, the detergent made with the aromatic monocarboxylate has a sterilizing ability and an antiseptic property.

The merits of the detergent composition of this invention are shown in the following Table 1 and Table 2.

TABLE 1.-EXAMPLE OF NONIONIC SURFACTANT LIQUID DETERGENT ADDED WITH SODIUM BENZOATE solubilizing agent 1 The maximum addition amount of potassium pyrophosphatc for Imagnagnmg the detergent in a transparent state at room temperature 2 The collar of a cotton shirt was cut into two portions, each ot which was washed with one oi the above-prepared detergents. Ten collars were used and the results obtained by a functional test were compared. Where there is diterence of readings above 2, it shows that there is a considerable difference between the detergency of the detergents. Conditions: Washed for 10 minutes at 20 C. with the 0.2% detergent and with a bath ratio o 1:30, using a vortex type electric washing machine; rinsed with water for 5 minutes 2 times. (Hereinafter, the relative detergency for naturally soiled clothes reers to the washing result obtained by the above-mentioned process.)

TABLE 2.-EXAMPLE OF PO'IASSIUM DODECYLBENZENE SULFONATE DETERGENT ADDED WITH SODIUM 1 Trademark of coconut aliphatic diethanol amide by Kawa-Ken Fine Chemical Co., Japan.

2 The minimum amount of glycols necessary for maintaining the liquid transparent at room temperature 0.).

It is considered that the solubilizing mechanism of the aromatic monocarboxylate in this invention is considerably different from the phenomenon stated by G. Noisillier. For example, an aqueous solution of sodium benzoate contributes to aid the dissolution of various compounds which are weakly soluble in water but does not contribute to soluibilize a surface active agent, such as potassium alkylbenzene sulfonate. However, by the addition of polyphosphate in the system of the surface active agent and the aromatic monocarboxylate, the surface active agent is solubilized remarkably and hence it is assumed that the Iphenomenon is completely different in its mechanism from the case of an aqueous solution of sodium benzoate alone. This fact can be seen in Table 3.

TABLE 3 Amount of solubilizing agent necessary for making transparent an aqueous 20% solution of potassium dodecylbenzene sulfonate (the state at 20C. after 24 hours)- Stabilizing agent: Quantity, wt. percent Sodium p-toluene sulfonate 20 1 Above 30.

Therefore, as shown in the above table, the use of the aromatic monocarboxylate is unsuitable for a light-duty liquid detergent composition containing a slight amount of or no polyphosphate. The inventors have confirmed that the solubilizing power of the aromatic monocarboxylate for the surface active agent is increased as the addition of the polyphosphate is increased and, thus conrmed, the result is applied to the formulation of a liquid detergent.

FIGURE 1 of the accompanying drawings is a graph showing the results obtained by investigating the amount of potassium pyrophosphate that can be added in an aqueous 5% solution of polyoxyethylene nonylphenyl ether (average mol number of ethylene oxide being 6.5) in regard to various hydrotropic agents. In FIGURE 1, the curve shows the limit of transparency of the composition, the domain below the curve shows the transparent homogeneous phase, and the domain above the curve shows the whiteturbid or separation phase.

FIGURE 2 isla graph showing the results of investigating as in the case of FIGURE 1 about an aqueous solution of potassium alkylbenzene sulfonate.

As clearly shown in the above figures, the solubilizing power of the aromatic monocarboxylate is better than that of a known lower alkylbenzene sulfonate.

The examples of the heavy-duty liquid detergent of this invention having the most suitable compounding ratios are as follows:

Compounding Example 1 Wt. percent Potassium dodecylbenzene sulfonate 10-30 Potassium pyrophosphate 10-40 Sodium p-toluate 5-20 Water to make Compounding Example 2 Polyoxyethylene nonylphenyl ether (average Water to make 100 atoms, (2) about 15 to 45% by weight of a potassium Compounding Example 4 polyphosphate selected from the group consisting of pyro- Dodecy-lbenzene sulfonic acid isopropanolaphosphate, tripolyphosphate and mixtures thereof, (3) mine 5-20 about l to 25% by weight of an alkali metal salt of an Polyoxyethylene nonylphenyl ether (average 5 acid having the structure:

mol number of ethylene oxide -20) 1-5 Imidazoline type amphoteric surfactant 1-5 Potassium pyrophosphate 10-40 R Sodium salicylate 5-20 Water to make 100 10 COOH It is desirable that the total amount of the noncationic surface `active agent and the polyphosphate is above by weight in the above compositions. in which R is a member selected from the group consist- Moreover, the composition of this invention may have ing of a hydrogen atom, a hydroxyl group and an alkyl added to it a suitable amount of additives, such as, foam l5 group having one to three carbon atoms, and (4) the controlling agents, fluorescent dyes, perfumes, anti-redepbalance water, the solid components in said composition osi-tion agents, coloring agents, corrosion inhibitors, solubeing less than 75% by weight. bilizers, and the like. 2. A detergent composition as claimed in claim 1 The practical examples of the heavy-duty liquid dewherein said acid is a member selected from the group tergent compositions of this invention are shown in the 20 consisting of benzoic acid, ethylbenzoic acid, p-toluic acid, following Table 4. p-cumic acid, and salicylic acid.

TABLE 4.-EXAMPLES OF HEAVY-DUTY LIQUID DETERGENT COMPOSITIONS Heavy- Heavy- Heavy- Heavyduty duty duty duty Weight percent liquid liquid powder powder detergent detergent detergent detergent Compounding Example No 5 (i 7 8 9 W S Z marketed marketed marketed marketed in U.S.A. in U.S.A. in U.S.A. in Japan Potassium alkylbenzene sulfonate (Cs-C15) 10 10 4 6 Polyoxyethylene nonylphenylether (P=5-10) 3 3 7 6 8 l-hydroxyethyl Z-undecyl 1midazoline Coconut fatty acid diethanol amide Sodium benzoate Sodium salicylate Sodium p-tolyate Potassium pyrophosphate Potassium tripolyphosphate Potassium metasilicate l 1 Fluorescent dye- 05 0.3 0.3 0.3 0.5 Perfume 0.1 0.1 0.1 0.1 0. 1 Water (to make) 100 100 100 100 100 Relative detergency for naturally soiled clothes 1 97 101' 99 99 100 1 Relative detergency of other detergents when the detergency of a heavy-duty power detergent T marketed in the U.S.A. is assumed to be 100. 2 S Stable.

3 Isopropanol amine salt.

4 Partly precipitated.

As will be clear from these examples, by utilizing the References Cited present invention, a transparent and homogeneous heavy- UNITED STATES PATENTS duty liquid detergent that can be easily used and has an 2,441,341 5/1948 Vitalis 252-3635 excellent detergency as compared with that of conven- 2,768,143 10/1956 Henry 252 3635 tional heavy-duty powder detergents can be obtained. 3 086 943 4/1963 Lang 252 152 The invention has been explained albove by specific 3101324 8/1963 WXOI; 252 138 examples but it should be understood that they are illus- 3:159581 12/1964 Diehl 252 152 tratilve only and that our invention is to be taken as limited 3,346,504 10/1967 Hen-mann 252 137 only by the scope of the appended claims.

The embodiments of the invention in which an exclusive OTHER REFERENCES property or privilege is claimed are defined as follows: Surface ACtlVe Agents and Detefgeflts, VOL II SChWal'Z 1. A transparent and homogeneous heavy-duty liquid et al IHGFSCGHCC P11131-, New York, 1958, P- 142- detergent composition consisting essentially of 1) about LEON D ROSDOL P E 5 to 30% by Weight of an anionic detergent surfactant 60 nary xamner selected from the group consisting of alkali metal, ams' D' SCHWARTZ: Asslsfanf Emmme monium and lower alkanolamine salts of alkylbenzene U S CL X R sulfonate having an alkyl group containing 8 to 15 carbon 252 152, 89J 138 

1. A TRANSPARENT AND HOMOGENEOUS HEAVY-DUTY LIQUID DETERGENT COMPOSITION CONSISTING ESSENTIALLY OF (1) ABOUT 5 TO 30% BY WEIGHT OF AN ANIONIC DETERGENT SURFACTANT SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL, AMMONIUM AND LOWER ALKANOLAMINE SALTS OF ALKYLBENZENE SULFONATE HAVING AN ALKYL GROUP CONTAINING 8 TO 15 CARBON ATOMS, (2) ABOUT 15 TO 45% BY WEIGHT OF A POTASSIUM POLYPHOSPHATE SELECTED FROM THE GROUP CONSISTING OF PYROPHOSPHATE, TRIPOLPHOSPHATE AND MIXTURES THEREOF, (3) ABOUT 1 TO 25% BY WEIGHT OF AN ALKALI METAL SALT OF AN ACID HAVING THE STRUCTURE: 